Mechanical response of the TiAl/steel brazed joint under torsional load

An attempt to investigate the mechanical response to the torsional load,torsional tests of TiAl/steel brazed joints were conducted at room temperature. The TiAl/steel joints used in the torsional loading tests were brazed under the optimum parameters of 1 173 K and 300 s. Torsional strength,fracture path and the behavior of the reaction phases were studied. The results show that the average torsional strength of the joints with the diameters of 13 mm,16 mm and 20 mm is 136 N·m,270 N·m and 490 N·m,respectively;which is 81. 9%,85. 5%and 86. 2%of the TiAl base metal,respectively. Fracture path and crack propagation process analysis shows,when subjected to the torsional load,Ag-based solid solution is deformed and cracks germinate at the interface of Ag-based solid solution/AlCu₂ Ti particles or Ag-based solid solution/AlCu₂ Ti layers,grow up and propagate into the Al-Cu-Ti brittle reaction layers,then propagate into the TiAl base metal,subsequently result in failure.